

Probably because they wouldn’t see a dime of revenue from this. It would be a new law that just says they have to do it. At best, they would be allowed to pass the costs to customers somehow, likely through our plate registrations at the DMV.
It’s basically a no win for the car companies. Lots of ill will, increased chance of litigation, increased costs for building cars, all for nothing.
In fact, I bet the car companies lobbyists are the reason we don’t have this already.
I thought the advantage of carpooling was saving money on gas and car maintenance. Also, environment.